Elevator



Jan. 1, 1935. J. H, BORDEN ET AL ELEVATOR Filed Ju ne 21,

1954 3 Sheets-Sheet l jruj enians W H- M FIRST FLOOR as 67 60' 4t Jan.1, 1935. .1. H. BORDEN ET AL ELEVATOR 1934 5 Sheets-Sheet 2 Filed June21 Jan. 1, 1935. J. H. BORDEN ET AL ELEVATOR Filed June 21, 1934 3Sheets-Sheet 3 frwerzi-onst- W ,q, M

UN RN l l I I l l L IIIIIHIIIIII'II lI-l k004i QZOUMW Patented Jan. 1,1935 ELEVATOR Joseph H. Borden, Elkins Park, and Nicholas R. Guilbert,Jr., Philadelphia, Pa., assignors to Atlantic Elevator Company,Philadelphia, Pa., a corporation of Pennsylvania Application June 21,1934, Serial No. 731,66;

23 Claims.

buildings.

In accordance with our invention, we have devised an elevator which maybe installed in an existing building with a minimum of alteration of thebuilding structures; one which requires the use of no shaft of thecustomary type and no unsightly mechanism or conspicuous structure whichwould be objectionable, for example, in a private home; and oneproviding a maximum of safety.

More particularly, in accordance with our invention, the guiding andpropelling mechanism for an elevator is enclosed within a singlehousing. The elevator car is external to the housing and is providedwith supporting members or brackets projecting through, and travellingin, a slot in the housing and connected with the guiding and propellingmechanism therein. The housing enclosing theguiding and propellingmechanism is preferably relatively small in cross-sectional areacompared to that of the car and may have the dimensions and structuralcharacteristics of an ordinary post of the building in which theelevator is installed, and may be finished to harmonize with theinterior decorations thereof.

More specifically in accordance with our invention, there is provided asingle vertical guiding member and a vertical screw in juxtaposition tothe guiding member, these twomembers being enclosed within a singlehousing. One or more supporting brackets or followers attached to theelevator car at vertically spaced points project through thelongitudinal slot in the housing and engage the vertical guiding member.One of these followers may include as a unitary part thereof a travelingnut cooperating with the vertical screw to propel the elevator carupwardly or downwardly, as desired. The vertical screw may be driven byany suitable means, such as an electric motor positioned beneath orabove the lowermost or uppermost floor of the car travel.

In accordancewith another feature of our invention, the limits of travelof the car are entirely above a given'floor as, for example, the firstfioor of a private home, and a safety treadle switch is disposed beneaththe elevator car and is connected to control the driving motor orpropelling mechanism of the car to prevent descent of the car in case aperson or object should be directly beneath the car.

For a better understanding of our invention, together with other andfurther features thereof, reference is bad to the following descriptiontaken in connection with the accompanying drawings and its scope will bepointed out in the appended claims.

In the drawings, Fig. 1 is a view of our elevator in front elevation,partly in section;

Figs. 2 and 3 are, respectively, a detailed top plan view 'and a view inelevation, partly in section of the car follower which engages thevertical guide and propelling screw;

Fig. 4 is'a perspective view of the enclosing housing for the propellingand guiding mecha- IllSm;

Fig. 5 is a view in side elevation of the upper and lowerfollowersshowing their vertical offset;

Fig. 6 is a circuit diagram of a control arrangement particularlysuitable for application to our elevator;

Fig. 7 is a fragmentary detail of a protective device which may beapplied to our elevator, while Fig. 8 is a. conventional representationof a limit switch which may beutilized in the control circuit of Fig.v6.

Referring now more particularly to Fig. 1 of the drawings, there isshown an elevator embodying our invention and adapted for travel betweenonly a first and a second floor. This elevator comprises a car 10 guidedand propelled by mechanism enclosed entirely within a single housing orhollow post 11. The car, when elevated from the first 'to the secondfloor passes through an opening 12 in the ceiling structure separatingthe first and second floor and this opening may be protected by asuitable railing and gate 13. The car 10 is supported by follower meansor guiding means comprising a pair of followers 14 and 15 secured to thecar 10 near its top and bottom, respectively.

A better understanding of the followers 14 and 15, together withpropelling and guiding mechanism with which they cooperate, may beobtained from Figs. 2 and 3 of the drawings which illustrate,respectively, top plan and longitudinal sectional views of the follower14. It will be seen that this follower comprises a substantiallyU-shaped bracket 16, one arm of which is attached to the side of the car10 by a pair of bolts 17. The inner arm 16a of the bracket 16 hasprojecting from opposite ends thereof extensions 16b which are joined bya horizontal web or plate member 160. The base member of the U-shapedbracket 16 travels in a vertical slot 11a in the housing 11. Supportedfrom the arms 161) are a pair of stub shafts 18 having their axesparallel to the side of the car 10 and secured to the brackets bysuitable lock nuts 19. Rollers 20 are mounted on the stub shafts 18,preferably with ball or roller bearings. Stub shafts 21 are also'securedin the arms 16?) by suitable lock nuts '22 with-their axesvertical to the side of the car 10 to which the follower 14 is attached.Rollers 23, similar to the rollers 20, are journalled on the stub shafts21, also preferably with ball or roller bearings.

Supported within the "housing 11' is a guide member 9 having achannel-shaped cross-section to the outer ends of the outstanding armsof which the guides 25 are secured by suitable bolts 26. The guides 25are also preferably of channel-shaped cross-section and have the innersurfaces and end surfaces of theirprojecting arms machined to form guidesurfaces.

As shown clearly in' Fig. 2, the rollers '20 engage and roll along theinner .surfaces of the lower farms .(as referred'to Fig. 2). "of the'guides 25, While the rollers 23 engage thee'nd surfaces of the upperarms (as referred to Fig. 2) of the guides 25, thus determining thelateral position of the car 10 inboth directions in'a plane normal tothe direction of travel. The web member 160 is. provided with a circularopening 2'7 through which passes a vertical propelling screw 28. .In'order to propel the car 10, a traveling nut 29 threaded on the screw '28is provided with an enlarged head 29 which is clamped between the "web1160 and 'afcollar '30 by means of cap screws 31.] The, threads of thenut 29 are preferably cut to provide a very loose fit with the threadsofthe screw 28 in order to prevent any bindingjbe'tween the nut '29 andscrew 28 occasioned by slight misalignment of the follower 14 and thescrew 28. The nut '29 maybe providedwith inserts32 of suitable bearingmaterial, such as bronze, babbitt or the like, to'procure a properalignment between the .nut 29 and the screw 28; I

Due to "the fact that the car 10 is supported entirely from one'side,its weightfwill produce atorque about the points of engagement of thefollowers 14 and 15 with the guides '25. This torquewill be in'such adirection that'the rollers of the upper follower 14 will bearagainst theguide surfaces adjacent the car 10 while the rollers 20 iof the follower115 will bear against the opposite guidesurfaces. This is shown moreclearly in the fragmentary view of Fig. "5, in which the near guide isomitted'forthe sake ofic'larity. From thisview, it will be seen that therollers 20 of the upper follower engage the right-hand guide surface ofthe guide 25, while the rollers 20' 'of the lower follower 15 engage theleft-hand guide surface of the guide 25. The diameter of the rollers20'is preferably sub.- stantially. smaller 'than the spacing of the armsof the guides 25'so that there'will be a'clearanced between'the roller20 of the follower l4 and the left-hand guide surface, and a similarclearance ,between .the roller 20' of the lower follower 1'5 and therigh'tehand guide surface. Inorder to prevent a tilting of the car 10occasioned by this pivotalmovement about the .followers :14 and 15, theroller 20 of the follower l4 is :prefera bly offset from the verticalwith respect to that of ;the follower 15, as shown in Fig.: 5... Thisarrangementjensures. that the car will remainv'ert-icalrat all times. in:spite of substantial clearance allowed between the rollers 20 and theguides 25 to prevent any possibility of binding.

By means of the mechanical propelling and guiding mechanism justdescribed, the car 10 may be raised and lowered by a singlesubstantially unitary guiding and propelling mechanism without anysubstantial swayxor lateral movement about the axis of the propellingscrew 28, As pointed out above, the weight of the car 10 exerts a torqueupon the rollers 20 against the opposite guide surfaces of the guides25. This weight of the car, acting through the pair of rollers 20laterally displaced, is more than sufficient to overcome any torqueexerted by the friction of the screw 28 with the nut 29, and maintainsthe car in a stable position, the rotation. of the screw providing onlya uniform vertical movement. Similarly, the upper and lower rollers 23prevent any movement of the car .10 about its horizontal axis ofsymmetry through the fact to which the followers '14 and 15 areattached' It will be seen that, in accordance with our" invention, thereis provided an elevator in which the car, is supported entirely from one"sideby propelling and guiding mechanism completely enclosed within asingle housing or hollow post which has a cross-sectional arearelatively small compared to that of the car. This housing or post 11may have a wood finish or other decorative' finish harmonizing with theinterior of the building in which the elevator is installed. Such asingle post of relatively small cross-sectional area results. in aminimum alteration of the existing structure of thebuilding and, at'thesame time, is substantially inconspicuous. Moreover, by the use of ascrew type of propelling mechanism, a maximum safety is procured, as thepitch of the screw is such that the weight offthe elevator will notreverse its movement. With such an arrangement, the car may convenientlybe elevated to the second floor, when not in use, in order still"further to minimize interference with the existingarrangement or use ofthe building in which the elevator is installed. V

The screw 28 is supported in the housing 11 by means of an upper bearingplate .or'bracket 33', a thrust bearing 33a, preferably of the ball orroller bearingtype, and a pairof lock nuts 34. It is also journalled ina lower bearing 35 secured underneath the first floor. By thussuspending the screw, it acts only as, a tension member in supportingthe car. and it may be much smaller in cross-section than if supportedfrom the bottom, in which case 'it would act as a vcolumn. On the end ofthe screw ,28 is mounted a pulley 36 which may be driven by a belt 37from the pulley 38 of a motor 39. Secured on the shaft of the screw 28is a brake drum 40 with which cooperates a brake shoe 41 biased tooperative position by a-spring 42. A solenoid 43 is provided forretracting the brake shoe 41 under certain conditions, asdescr'ibed morefully hereinafter.

While any suitable control scheme may be utilized for controlling themotor 39 .propellingthe elevator, we have illustratedinFig. 6 a diagramof a control circuit particularly adapted for use with our ,elevator.The motor 39'of Fig.1 is shown in Fig. 6 as being of the capacitor typeand is essentially a 2-phase induction motor, one phase of which ;isenergized directly from a single-phase alternating current supplycircuit and the other, from the supply circuit through phase-shiftingcapacitors. The control system comprises essentially a plurality ofcontrol switches S located in the elevator car and on the several floorsbetween which the elevator operates, in the case illustrated, only'afirst and a second fioor; up contactor or relay U1; a down contactor orrelay D1 and an. accelerating relay A. The contacts U2 and D2 of thecontactors U1 and D1, respectively, serve to connect supply lines L1 andL2 with either polarity directly to the terminals 390. and 39b of themotor 39, constituting one phasewinding. The adjacent contacts U2 andD2, as viewed in Fig. 6, are connected directly in parallel and serve toconnect the line L1 to the terminal 39c, while the other terminal 39d ofthe same motor phase-winding is connected through capacitors C1 and C2,in parallel, to the other line L2. Thus, the phase of thevoltages'impressed upon the two phase windings of the motor 39 aredisplaced to provide a polyphase magnetomotive force therefor, and torender it capable of starting from a single-phase alternating currentcircuit.

The lines L1, L2 are connected to the control circuit through the fusesF, the line L1 being connected to one side of the operating coils of therelays U1, D1. The line L2 is connected to the control switches S,located on the several floors and in the elevator car, through aconductor 44 leading to a gate switch G, of any suitable well-knowntype, which serves to interrupt the control circuit except when the gateof the car is closed. The other terminal of the switch G is connected toa conductor 45 interconnecting the blades of the several controlswitches S. The up contacts U of the several switches S are connectedtogether to a common conductor 46 which is connected to an upper limitswitch B2, the other terminal of which is connected to a returnconductor 4''! connected, in turn, to the other terminal of the windingof the relay U1. Similarly, the down contacts D of the several switchesS are connected to a common conductor 48 which is connectedto oneterminal of a lower limit switch B1, the other terminal of which isconnected to a return conductor 49 and, through the contacts T2 of asafety relay T1, (to be described hereinafter) to the other terminal ofthe winding of the relay D1. As described above, the capacitor C2 isconnected in parallel with capacitor C1 through the contacts A1 of anaccelerating relay A, thetwo capacitors being included in series withthe motor terminal 39d. The operating coil of the accelerating relay Ais connected between the motor terminals 390 and 39d through its owncontacts A1.

The limit switches B1 and B2 may be of any of the types well-known inthe art, though there is illustrated schematically in Fig. 8 onearrangement suitable for use in our control system. In this arrangement,a pair of normally-closed contacts 52 are enclosed within a suitablehousing and connected to terminals 53, one of the contacts being fixedin the housing, while the other is mounted on a cam 54 pivoted in thehousing at 55. The structure is mounted so that the cam 54 lies in thepath of travel of an operating rod 56 attached to the follower 14 (Fig.2). Engagement of the cam 54 by the operating rod 56 is effective toopen the contacts 52.

The operation of the above-described control system will be wellunderstood by those skilled in the art. In brief, assuming that the caris at the second floor, as indicated in the diagram of Fig.5, and thatit is desired to proceed to the first floor, any of the control switchesS may be operated to close its respective down contact D. Assuming thegate of the car to be closed, so that the gate switch G is closed, thecontrol circuit may then be traced from the line L2, fuse F, conductor44, gate switch G, conductor 45, switch S, conductor 48, lower limitswitch B1, return conductor 49, contacts T2, operating coil of relay D1,fuse F to L1. The relay D1 closes its contacts D2 which, as describedabove, connects the lines L1, L2 directly to.the motor terminals 39a.and 39b and also connects the lines L1, L2 to the terminals 39c, 39dthrough the capacitors C1, C2 connected in parallel. Simultaneously, thesolenoid coil 43, connected between the motor terminals 39a, 39b, isenergized and retracts the brake shoe 41 (Fig. 1) against its biasingspring 42. The motor 39 starts and rotates the screw 28 in such adirection as to return the car to the first floor.

The car will proceed only so long as the particular switch S which hasbeen operated is retained in engagement with its down contact D. Whenthe elevator reaches the proper level at the first fioor, the operatingrod 56 on the follower 14 engages the limit switch B1 opening thecircuit of the return conductor 49 thereat and deenergizing the downrelay D1 which, in turn, deenergizes the motor and the retractingsolenoid 43; thereupon, the motor stops and the brake 41 is applied tostop the car. In case it is desired to move the car back to the secondfloor, any one of the several control switches S is moved to engage theup contact U, thus energizing the return conductor 4'? by means of acircuit similar to that described above to excite the operating coil ofthe up relay U1, which connects the motor terminals 39a, 39b to thelines L1, L2 with a reverse polarity. At the same time, the solenoidbrake 41-42-43 is released and the motor rotates in a reverse direction,propelling the car to the second floor. As in the downward movement, themotor of the car will be stopped at the proper level by the engagementof the operating rod 56 with the limit switch B2.

When our elevator is to be operated upwardly only from a given floor as,for example, the first floor, it is desirable to have a protectivedevice to prevent the descent of the elevator upon any person or objectthat may have chanced beneath the car. This is accomplished in thesystem shown in Fig. 6 by means of a treadle or safety switch or mat T,which may conveniently be made relatively thin for placement under a rugor carpet. The contacts of the treadle switch T may be connected toenergize the operating coil of the relay T1 directly from the lines L1,L2 through the down control circuit, but preferably, as shown, a voltagereducing transformer 50 is included in this circuit. One terminal of theprimary winding of the transformer 50 is connected directly to theterminal L1 through the fuse F, while the other is connected to the downreturn conductor 49 so that the transformer 50 is energized whenever thedown control circuit is completed. The secondary winding of thetransformer 50 is connected to energize the operating coil of the relayT1 in series with the contacts of the treadle switch T which may thus bedesigned for a very low voltage.

Upon, the occurrence ofa person or anyot-her body beneath theelevatorcar and the operation of any of the controlswitches to the, downcontact, the transformerv 50 -Wl11':be energized from the down returnconductor 49 and, at the same time, the circuit of the coil of the relayT1 will be completed by thev safety switch T and the relay T1 willoperate toopen its contacts T2 which are in series with'the operatingcoil of the down relay D1. The relay-D1 willthus 'be deenergized to stopor. prevent the operation of the motor 39 in such a direction as tolower the car.-. It will be noted, of course, that the up control vcircuit is completely independent of the treadle switch T, so that thecar may, at any time, be operated upwardly and away from any person orvobject therebeneath.

In Fig. 7, there is illustrated a safety device which maybe applied toour elevator to interrupt its operation in case the threads of the screw28 or the nut 29 become worn to 2. dangerous degree. This devicecomprises a pair of cooperating contacts 57'mounted on a bracket 58,supported from the traveling nut 29, and on a reciprocable member 59retained in position by suitable guides 60 and biased to maintain theengagement of the contacts, by a spring 61. From the member 58 depends arod 62 to which is attached an auxiliary follower extending into theroot of the thread of-the screw 28. The contacts 57 may preferably beincluded in the main supply conductor 44 to the control switches S andconnectedin' series with the contacts of the gate switch G. Duringnormal operation,-

the safetycontacts 57 are inoperative. However, in case the thread ofeither the screw 28 or-the nut 2 9'should become worn to a dangerousdegree, the auxiliary follower 63 will be lowered a corresponding amountand will finally engage the top of the-thread immediately below the rootwhich it" normally follows. This'engagement will be effective to raisethe depending rod 62 and'to break thecircuit of the contacts 57, thusinterrupting the supply circuit to the control switches and renderingthe elevator inoperative. Y I

While we have described-what we at present consider the'preferredembodiment of our invention, it will be obvious to thoseskilled in the art that various changes and modifications may be-madewithout' depar-ting from our invention and we, therefore, aim in theappended claims to cover all 'such changes and modifications as fallwithin the true spirit and scope ofour invention.v Y in What we claimis: An. elevator comprising .a vertical guide structureprovided with aplurality of vertical guide surfaces, a car external to said guidestructure, the guide surfaces of said structure being spaced bydistances which are small relative to'the'dim'ensions of the car,follower means s'ecuredxto said car-and engaging said guide surfacesatsubstantially and vertically spaced points, andmeans forpropellingsaid car comprising a single continuous vertical screwinjuxtaposition to all of said guide surfaces and a complete nutcooperating therewith, one of said screw and nut elements being-securedto said car. 2.-An I elevator] comprising a. single unitary verticalguide structure provided with a plurality of vertical guide surfacea'iacar external to :said guide structure, the guide surfaces of saidstruc-' ture being spaced'i'by distances which are small relative to thedimensions of thecar, follow (single unitary or means secured to 2 "saidcar and-rengaging said guide surfaces at verticallyspaced points nearthe top-and bottom of said car respectively,rand.means for propellingsaid car comprising a single vertical screw in juxtaposition to all ofsaid guide surfaces and a com-, plete nut cooperating therewith andsecured to said car. 7 .p'

3.' An elevator comprising a single unitary vertical guide structureprovided with a plurality of verticalguide surfaces, acar external tosaid guide structure, the guide surfaces of said 'structure being spaced:by-distances which are small relative to the dimensions of the car,follower means secured to said .lcariand engaging said guide surfaces atvertically spaced points and in two planes inclined to. eachother and.parallel to the direction'of travel, and means for propelling said carcomprising a single vertical screw in vjuxtaposition to all of saidguide surfaces and a .nut cooperating therewith and secured to said car.

4. An elevator comprising a single unitary vertical guide structureprovided with a plurality of vertical guide surfaces, a car external tosaid guide structure, .theguide surfaces of said structure being spacedby distances which are small relativeto the dimensions of the car, apair of followers secured to one side of said carat vertically spacedpoints and engaging said guide surfaces -in a plane parallel to saidside of the car and also in .a plane perpendicular thereto andparallelto the direction of travel, and means for propelling said carcomprising asingle vertical screw in juxtaposition to all of said guidesurfaces and a nut cooperating therewith and secured to said car. x

5. An elevator comprising a single unitary vertical guide structurehaving a substantially channel-shaped cross-section provided with aplurality of vertical guide surfaces, a car external to said guidestructure, the guide surfaces of said structure being spaced bydistances which are small relative to the dimensions of the car,follower means secured to said'car and engaging said g'uide surfaces atsubstantially and vertically spaced points, and means for propellingsaid car comprisinga single continuous vertical screw disposed Withinsaid guide channel and a complete nut cooperating therewith and securedto said car. 7

6. An elevator comprising a single unitary vertical guide structureincluding a pair of 0pposed channel members each havingguide surfacesnormal to'each-other, a-car external to said guide-structure, the guidesurfaces of said structure being -spaced by distances which are smallrelative to the dimensions of the car, a pair of followers secured tosaid car at vertically spaced points, each of said followers having apair of rollers mounted on axes in planes normal to each other andengaging said normal guide surfaces, and means for propelling-said carcomprising a single vertical screw'in' juxtaposition to all of saidguide surfaces and afnut'cooperatingtherewith and secured to said car. r

7. An elevator comprising a single unitary vertical guide structure, acar external to'said guide structure,-a pair of followers secured tosaid :car at vertically spaced points and engaging said guide, and meansfor propelling said car comprising a single continuous vertical screw injuxtaposition to'said guide, one of said followers including a completenut "cooperating with said $crew ,7

8. An elevator comprising a single unitary vertical guide structureincluding a pair of opposed channelmembers provided with a plurality ofvertical-guide surfaces,.a car external to said guide structure, theguide surfaces of said structure being spaced by distances, which aresmall relative to the dimensions of. the car, a pair of followerssecured to said car at vertically spaced points, each of said followershaving rollers engaging said opposed channel members, and a singlevertical screw disposed between opposed channel members, one of saidfollowers including a nut cooperating with said screw.

9. An elevator comprising a single unitary vertical guide structureincluding a pair of opposed .channel members, a. car external to saidguide structure, and a pair of followers secured to said car atvertically spaced points, each of said followers having a pair ofrollers each engaging an inner surface of an arm of one of said opposedchannels and having also a pair of rollers each engaging an end surfaceof an arm of one of said channels.

10. An elevator comprising a single unitary vertical guide structureprovided with a plurality of vertical guide surfaces, a car external tosaid guide structure, the guide surfaces of said structure being spacedby distances which are small relative to the dimensions of the car, anda pair of followers secured to one side of the car at vertically spacedpoints, said guide structure including a pair of opposed guidingsurfaces parallel to said side of the car, and said followers havingmembers interposed between said opposed guide surfaces with asubstantial clearance, said follower members being olfset from thevertical with respect to each other by a distance equal to saidclearance.

11. An elevator comprising a single unitary vertical guide structureprovided with a plurality of vertical guide surfaces, a car external tosaid guide structure, the guide surfaces of said structure being spacedby distances which are small relative to the dimensions of the car,follower means secured to said car and engaging said guide surfaces atsubstantially and vertically spaced points, and means for propellingsaid car comprising a single vertical screw in juxtaposition to all ofsaid guide surfaces, means for rotating said screw without longitudinalmotion, and a complete travelling nut cooperating with said screw andsecured to said car.

12. An elevator comprising a single unitary vertical guide structureprovided with a plurality of vertical guide surfaces, a car external tosaid guide structure, the guide surfaces of said structure being spacedby distances which are small relative to the dimensions of the car,follower means secured to said car and engaging said guide surfaces atsubstantially and vertically spaced points, and means for propellingsaid car comprising a single vertical screw in juxtaposition to all ofsaid guide surfaces, means for rotating said screw, bearing means forretaining said screw from longitudinal motion, and a complete travellingnut cooperating with said screw and secured to said car.

13. An elevator comprising a single unitary vertical guide structure, acar external to said guide structure, follower means secured to said carand engaging said guide at substantially and vertically spaced points,and means for propelling said car comprising a single suspended verticalscrew in juxtaposition to said guide structure,

and a travelling nut cooperating therewith and secured to said car.

14. An elevator'comprising a single unitary vertical guide structureprovided with a plurality of vertical guide surfaces, a car external tosaid guide structure, the guide surfaces of said structure being spacedby distances which are small relative to the dimension of the car,follower means secured to said car and engaging said guide surfaces atsubstantially and vertically spacedpoints, a propelling screw mountedadjacent all of said guide surfaces, a thrust bearing disposed near theupper end of said guide supporting said. screw, and a completetravelling nut cooperating therewith and secured to said car. i i

15. An elevator comprising a single vertical housing provided with avertical slot and containing a single unitary vertical guide structureand a single vertical screw, a car external to said housing, andsupporting brackets attached to one side only of said car and connectedto said guide structure and said screw, said brackets travelling in thevertical slot in said housing.

16. An elevator comprising a single vertical housing containing a singleunitary vertical guide structure, a single vertical screw suspendedwithin said housing, a car external to said housing, the cross-sectionalarea of said housing being relatively small compared with that of saidcar, and supporting means attached to said car and connected with saidguide structure and with said screw.

17. An elevator comprising a single unitary vertical guide structure, acar, follower means secured to said car and engaging said guidestructure at substantially and vertically spaced points, means forpropelling said car comprising a single vertical screw in juxtapositionto said guide structure and a nut cooperating therewith, one of saidscrew and nut elements being secured to said car, and a single housingenclosing said guide structure and said screw and having across-sectional area small compared to that of said car.

18. An elevator comprising a single unitary vertical guide structure, acar, follower means secured to said car and engaging said guidestructure at vertically spaced points, a single screw in juxtapositionto said guide structure for propelling said car, and a single housingenclosing said guide structure and said propelling means and providedwith a vertical slot in which travels said follower means.

19. An elevator comprising a single vertical housing containing guidingand propelling means, a car external to said housing and adapted totravel upwardly only from a given floor, said floor extending under thecar, and means responsive to the presence of a body beneath the car forpreventing the descent of the car.

20. An elevator comprising a single vertical housing containing guidingand propelling means, driving means for said propelling means, a carexternal to said housing and adapted to travel upwardly only from agiven floor, said floor extending under the car, and a treadle switchdisposed on the floor beneath said car and connected to control saiddriving means to prevent the descent of the car upon a body disposedbeneath the car.

21. An elevator comprising a single vertical housing containing guidingand propelling means, an electric motor connected to drive saidpropelling means, a car external to said housing and; having? limits: oftravel. entirely abovema. given floor, said floor extending under thecar, up and down control circuits for said motor, and a treadle'switchdisposed on. the floor beneath. said. car and included in the downcontrol circuit of said motor to deenergize the same upon the occurrenceof a body beneath the car.

22. An elevator comprising a single unitary vertical guide structure, acar external to said guide structure, follower means secured to said carand engaging. said guide structure at sub stantially and verticallyspaced points, and means for propelling said car comprising a singlecontinuous vertical screw in juxtaposition to said guide, said followermeansincluding a.

with. auxiliary bearing means for maintaining said screw and nut inproper alignment.

23'. An elevator comprising as single unitary vertical guide structure,a car external to said guide structure, follower means secured to saidcar and engaging'said' guide structure at substantially and verticallyspaced points, and

means for propelling-said car comprising a single continuous verticalscrew in juxtaposition to said guide, said. follower'means including anut threaded on said screw with a substantial clearance and. providedwith a pair of auxiliary bear ing inserts for maintaining said: screwand nut in proper alignment;

- JOSEPHI H. BORDEN'.

, NICHOLAS R; GUILBERT, JR.

CERTIFICATE OF CORRECTION.

Patent No. 1,986, 620. January 1. 1935.

JOSEPH H. BURDEN, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 5,second column, line 8, claim 14, for "dimension" read dimensions; andthat the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 12th day of February, A. D. 1935.

Leslie Frazer (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,986, 620. January 1, 1935.

k- JOSEPH H. BORDEN, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 5,second column, line 8, claim 14, for "dimension" reed dimensions; andthat the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 12th day of February, A. D. 1935.

Leslie Frazer (Seal) Acting Commissioner of Patents.

